Yes, that's the Apple proprietary connector used for charging, at least until the iPhone 15, which uses a USB-C port/jack. (You can thank the EU for this change, supposed to reduce the number of different chargers you have, but, of course, it still doesn't solve the no 3.5mm headphone jack problem, so you need to add another adapter to the collection...)
3.5 mm headphone jack comes in handy for hooking up to vintage hi fi gear. If anyone back then were to mention bluetooth, you’d tell them to go see a dentist